lttd/lttd.c

   1 /*
   2  * lttd
   3  *
   4  * Linux Trace Toolkit Daemon
   5  *
   6  * This is a simple daemon that reads a few LTTng debugfs channels and saves
   7  * them in a trace on the virtual file system.
   8  *
   9  * CPU hot-plugging is supported using inotify.
  10  *
  11  * Copyright 2009-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  12  * Copyright 2010 - Michael Sills-Lavoie <michael.sills-lavoie@polymtl.ca>
  13  * Copyright 2010 - Oumarou Dicko <oumarou.dicko@polymtl.ca>
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation; either version 2 of the License, or
  18  * (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License along
  26  * with this program; if not, write to the Free Software Foundation, Inc.,
  27  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  28  */
  29
  30 #ifdef HAVE_CONFIG_H
  31 #include <config.h>
  32 #endif
  33
  34 #define _REENTRANT
  35 #define _GNU_SOURCE
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <signal.h>
  40 #include <errno.h>
  41
  42 #include <liblttd/liblttd.h>
  43 #include <liblttd/liblttdvfs.h>
  44
  45 struct liblttd_instance* instance;
  46
  47 static char             *trace_name = NULL;
  48 static char             *channel_name = NULL;
  49 static int              daemon_mode = 0;
  50 static int              append_mode = 0;
  51 static unsigned long    num_threads = 1;
  52 static int              dump_flight_only = 0;
  53 static int              dump_normal_only = 0;
  54 static int              verbose_mode = 0;
  55
  56
  57 /* Args :
  58  *
  59  * -t directory         Directory name of the trace to write to. Will be created.
  60  * -c directory         Root directory of the debugfs trace channels.
  61  * -d                   Run in background (daemon).
  62  * -a                   Trace append mode.
  63  * -s                   Send SIGUSR1 to parent when ready for IO.
  64  */
  65 void show_arguments(void)
  66 {
  67         printf("Please use the following arguments :\n");
  68         printf("\n");
  69         printf("-t directory  Directory name of the trace to write to.\n"
  70                                  "              It will be created.\n");
  71         printf("-c directory  Root directory of the debugfs trace channels.\n");
  72         printf("-d            Run in background (daemon).\n");
  73         printf("-a            Append to an possibly existing trace.\n");
  74         printf("-N            Number of threads to start.\n");
  75         printf("-f            Dump only flight recorder channels.\n");
  76         printf("-n            Dump only normal channels.\n");
  77         printf("-v            Verbose mode.\n");
  78         printf("\n");
  79 }
  80
  81
  82 /* parse_arguments
  83  *
  84  * Parses the command line arguments.
  85  *
  86  * Returns 1 if the arguments were correct, but doesn't ask for program
  87  * continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
  88  */
  89 int parse_arguments(int argc, char **argv)
  90 {
  91         int ret = 0;
  92         int argn = 1;
  93
  94         if(argc == 2) {
  95                 if(strcmp(argv[1], "-h") == 0) {
  96                         return 1;
  97                 }
  98         }
  99
 100         while(argn < argc) {
 101
 102                 switch(argv[argn][0]) {
 103                         case '-':
 104                                 switch(argv[argn][1]) {
 105                                         case 't':
 106                                                 if(argn+1 < argc) {
 107                                                         trace_name = argv[argn+1];
 108                                                         argn++;
 109                                                 }
 110                                                 break;
 111                                         case 'c':
 112                                                 if(argn+1 < argc) {
 113                                                         channel_name = argv[argn+1];
 114                                                         argn++;
 115                                                 }
 116                                                 break;
 117                                         case 'd':
 118                                                 daemon_mode = 1;
 119                                                 break;
 120                                         case 'a':
 121                                                 append_mode = 1;
 122                                                 break;
 123                                         case 'N':
 124                                                 if(argn+1 < argc) {
 125                                                         num_threads = strtoul(argv[argn+1], NULL, 0);
 126                                                         argn++;
 127                                                 }
 128                                                 break;
 129                                         case 'f':
 130                                                 dump_flight_only = 1;
 131                                                 break;
 132                                         case 'n':
 133                                                 dump_normal_only = 1;
 134                                                 break;
 135                                         case 'v':
 136                                                 verbose_mode = 1;
 137                                                 break;
 138                                         default:
 139                                                 printf("Invalid argument '%s'.\n", argv[argn]);
 140                                                 printf("\n");
 141                                                 ret = -1;
 142                                 }
 143                                 break;
 144                         default:
 145                                 printf("Invalid argument '%s'.\n", argv[argn]);
 146                                 printf("\n");
 147                                 ret = -1;
 148                 }
 149                 argn++;
 150         }
 151
 152         if(trace_name == NULL) {
 153                 printf("Please specify a trace name.\n");
 154                 printf("\n");
 155                 ret = -1;
 156         }
 157
 158         if(channel_name == NULL) {
 159                 printf("Please specify a channel name.\n");
 160                 printf("\n");
 161                 ret = -1;
 162         }
 163
 164         return ret;
 165 }
 166
 167 void show_info(void)
 168 {
 169         printf("Linux Trace Toolkit Trace Daemon " VERSION "\n");
 170         printf("\n");
 171         printf("Reading from debugfs directory : %s\n", channel_name);
 172         printf("Writing to trace directory : %s\n", trace_name);
 173         printf("\n");
 174 }
 175
 176
 177 /* signal handling */
 178
 179 static void handler(int signo)
 180 {
 181         printf("Signal %d received : exiting cleanly\n", signo);
 182         liblttd_stop_instance(instance);
 183 }
 184
 185 int main(int argc, char ** argv)
 186 {
 187         int ret = 0;
 188         struct sigaction act;
 189
 190         ret = parse_arguments(argc, argv);
 191
 192         if(ret != 0) show_arguments();
 193         if(ret < 0) return EINVAL;
 194         if(ret > 0) return 0;
 195
 196         show_info();
 197
 198         /* Connect the signal handlers */
 199         act.sa_handler = handler;
 200         act.sa_flags = 0;
 201         sigemptyset(&(act.sa_mask));
 202         sigaddset(&(act.sa_mask), SIGTERM);
 203         sigaddset(&(act.sa_mask), SIGQUIT);
 204         sigaddset(&(act.sa_mask), SIGINT);
 205         sigaction(SIGTERM, &act, NULL);
 206         sigaction(SIGQUIT, &act, NULL);
 207         sigaction(SIGINT, &act, NULL);
 208
 209         if(daemon_mode) {
 210                 ret = daemon(0, 0);
 211
 212                 if(ret == -1) {
 213                         perror("An error occured while daemonizing.");
 214                         exit(-1);
 215                 }
 216         }
 217
 218         struct liblttd_callbacks* callbacks =
 219                 liblttdvfs_new_callbacks(trace_name, append_mode, verbose_mode);
 220
 221         instance = liblttd_new_instance(callbacks, channel_name, num_threads,
 222                                         dump_flight_only, dump_normal_only,
 223                                         verbose_mode);
 224
 225         if(!instance) {
 226                 perror("An error occured while creating the liblttd instance");
 227                 return ret;
 228         }
 229
 230         liblttd_start_instance(instance);
 231
 232         return ret;
 233 }
 234